Semi-automatic telephone system.



I A. H. wuss. SEMI-AUTOMATIC TELEPHONE SYSTEM.

APPL IUATION FILED MAR. 28, 1908.

Patented Nov. 17, 1914.

2 SHEETSSHEET 1.

A. H. WEISS.

SEMIAUTOMATIO TELEPHONE SYSTEM.

APPLICATION FILED MAR. 28, 1908.

mtented Nov. 17, 1914.

i5 2 SHEETS-SHEET 2.

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mYme ssa-fi 25 m 2 2@M v mwm w" M QWM UNITED STATES P a TE1\ *T-ormo-E. 1

ALFRED H. WEISS; OF CHICAGO, ILLINOIS,

assist? a To I KELL0GG swrrcnnoann Ami SUPPLY COMPANY, OF CHICAGO, ILLINOIS, J.- CO RPOBATION CFILLINOIS} snmr-auroma'rlc TELErHonE 'sysrniii. v

Specification of Letters Intent.

To all whom it may concern Be it known that I, ALFRED H. \Vnrss, a citizen of the United States, residing in Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Semi-Automatic Telephone Systems, of which the following is a specification, i I

My invention relates to telephone systems of theclass known as semi-automa'tic systems,'or that class of systems in which a portion ofthe operation necessary for completing afconversational connection is accomplished automatically and the rest accomplished manually. a In my system a switchboard of theusual multiple type is used, each section of'the switchboard being provided with a number of cords and multiple" jacksbut having no answering-jacks and no signals individual to the lines terminating in the board.

Generally speaking, the operation ofiny system is as follows: When a party removes his receiver from the switch hook automatic mechanism at the central oflice is set into motion and' connects one of the cord circuits of the switchboard directly with the calling,

J line, thus saving the time usually required for the operator to raise her answering plug and insert it into the answering jack. The

remainder of the operation, that of obtaining a desired number, plugginginto the multiple jack of the desired line, ringing and receiving the disconnect signals, is thelsame' as in any manual switchboard. It willthus be seen that by,the use of my invention a less number of operators will be required to handle the calls of a given number of subscribers because a part of the work usually performed by the operator is automatically performed by the mechanism ofthesy'stem,

Further advantages of my system over the fully manual systems arise from thefl-de:

crease in the original cost, of installation,-

the system of my invention requiring acon fiiderably less number j of switchboard sections a given number of lines.

i In my system I provide for each switch board section an idle cord selector which automatically steps forward one step for each new. connection and is constantly in,

connection with the next idle cord circuit,

such can a the cord s of a pos s]; will be used in sequence.

My System also has a ll' lectorfl-foii wwhat subscriber is clal'liiigj z' 1 It will be understood that apparatusshown in this application-is typical and that the system may bechange anmanydetailsto operate-with automatic con nectors of diiferi-nit.v construction than-those herewith illustrated and that, the niechanicala part of this invention. v

- [luv invention isillustrzited in the accompanying drawings'in which- J -I 5} Figure lflrepresents a calling and called i telephone 'line and the apparatus-;which would come into operation in-completing 7 the connection --between the two lines," the line on the left hererepre'sentingthe calling telephone line, and Figl-2represents three connecting circuits and the r'elation' 'they hear one to the other and ,to the cord;selec- Referring to Fig.1, "the subscribers station L is equipped withQthe annunciator 2 :1: and condenser 3'ii i apermanentbridge v b e-- tween theline conductors ,4 and 5, and-with the transmitter '6- and receiver -7 in abridge maintained normally opex'rby 'contacts lof the switch-hook.8. At the central otfice line-2::

'constructionlofthe connector itself forms no i 7 5 conductor 4=connects through contacts 9 and 10 of cut-ofi'relay' 1'1,-conductor. 12, the coil oi linerelay13, contacts 14 and 15 of relay 13,-- the battery'normal 25 and the closed contacts 26 and 16 of the master relay 17 with thelive pole of battery A. The other line i'qf the The contact 20 is connected through the coil of relay 11 to earth, and through conductor 22 with the sleeve contacts 23 of the multiple jacks, and with snring 34 of the line relay 13 and contact 37 of the line' connector 36, and the contact 21 is connected with the tip contacts 24 of the multiple jacks and with nected with earth and contact being con- 4 nected with the common conductor 31 which.

connects through the coil of the master relay 17 with the live pole of battery A. Relay 13 also has the normally open contacts 33 and 84, contact 33 being connected with the "co ntact'35 of the line connector 36 and contact 34 being connected as before described.

The called subscribers line is equipped with apparatus identical with the apparatus of the calling line and the corresponding apparatus of this line is here designated by like figures with the sulfix The called subscribers line shown is one of the subscribers lines which terminates at the same switchboard section with the calling subscribers line. If, however, this subscribers line had been 'one which terminated at another section, the connections would he the same except that contacts 15 and 30 would i connect to another pair of common conductors than 25 and 31, and contacts 33' and 34 and the conductor 39 would connect to i the contacts of another line connector and not with the line connector 36. v

The cord circuit for completing the connection between the calling and called lines has the tip strand extending frcmthe contact spring 42 of the line connector 36 through conductor 43, condenser 44, conductors 45 and 46, contacts 18 and 47-of the opcrators ringing key 49 to the tip contact 50 of the calling plug. The cord-circuit also has the sleeve talking strand extending (luring conversation from the brush 552 of the line connector 36 through conductors 53 and 54, condenser 55, conductor 56 and the contacts 57 and 58 of the.- operators'ringing key 49 to the sleeve contact 59 of the calling plug. The line connector has the third or private contact. 62 which is normally connected through conductor 63 and contacts 64 and 65.611 supervisory relax 66 with the sleeve cord conductor 54,

7 The line connector which is constructed on the well known step by step principle has a H't l' molar-ts 35. 37ainl 38. and 335. 37 and' 38. etc. for each line terminating at the position. This connector has the ratchet wheel 67 adapted to be engaged by the pawl 68 when the rotary magnet 69 is actuated. The energization of the magnet 69 moves its armature 70. and causes the contacts 71 to be separated such that the magnet continues to actuate, making and breaking its own circuitwhen the circuit through the rotary magnetGO is closed; A's the pawl 68 moves toward the electro-magnct 69 on its first stroke the extension 78 engages the extension 7.) upon the release dog 72 moving the latter such that its'projection .73 is disengaged from the projectionf7-1upon the retaining pawl 75, thus allowing the retaining pawl to engage the ratchet 67 to prevent the wheel from returning to its normal position due to the tension coil spring not shown. The release magnet 76 issadapted,

when energized, to attract its armature 77 and move the dog 72 such that its projection 73 again engages the projection 74 upon. the retaining pawl 75 drawing the pawl 75 away from the ratchet wheel when the release magnet is again deenergized. 'The parts here shown are only intended-to rep? resent the mechanical construction. of my connector in a conventional way, the details of this connector being shown and described in another application. I

The cord circuit proper has four relays- 66, 80, 81 and 82corresponding to the tip and sleeve relays of-the well-known twowire manual cord circuit. The relay 66 has,

in addition to the contacts previously described, the contact 83, which is adapted to 6 make connection with contact 65 before that contact is separated from the contact 64, this type of relay being known as a make before break relay. The contact 83 is connectedwith-conductor,53. Relay 66-also has 105 the normally closed contacts 84 and 85, the

contact 84 being connected with the live pole of battery C and the contact 85 being connectcdthrou'gh conductor 86 with the coil of the rotary magnet 69 and also With llo The other one terminalof-the signal 87. terminal of the signal 87'connects with the normally open contact 88 of relay 80, the latter relay also having the contact 89 connected with earth and adapted to connect with contact 88 ,when the relay is actuated.

The contact .88 is alsoconnected through-the normally closed contacts 90 and 9101' relay with thesignaI-QQ, the other terminal of this signal being connected with the live 1 pole of battery C. i

.Therelay 81 has its coil connected between the tip strand 43 and the normally disconnectcd contact93 of the operators listening key 94. the contact 93 being adapted to con- 5' ncct with earth through contact 95 when the key is actuated. Relay 81 has normally open contacts 96 and 97 in parallel with the contacts 93 and 95 adapted to complete a locking circuit for the relay 81. This relay 1 also has the normally tact 105 is normally connected stance closed contacts 98 and 99, the contact 98 being connected through the signal 100 with earth and the contact 99 being connected with the normally open contact 101 of relay 66. The contact 99 of relay 81 is adapted to connect with contact 102 of that relay when the relay is actuated, this contact 102 being connected through conductor 103 and the coil of release magnet 76 with earth. The relay 80 also has the normallyppen contacts 104 and 105 maintaining 'a normal separation between conductors 45 and 46 of the cord circuit. Conthrough contact 106 with the normally open auxiliary contact 107 of the operators listening key 94, this contact being adapted to be connected with the contact 108 when the key is actuated, the contact 108 being connected with the impedance coil 109 and with one terminal of the condenser 110, the other terminal of this condenser being connected through the tertiary of the operators induction coil with the live pole of battery 0.

The operators receiver 111 is adapted to be placed in a bridge between the talking strands of the cords by the actuation of the operators listening key 94. The contact 101 of relay 06 is also connected through con ductor 112 with the contact 113 of the idle cord selector 114. This cord selector is adapter to automatically step its brushes 115 and 116 forward step by step so that the brush 116 normally stands in contact with one of the contacts 117, which connects with an idle line connector 'or, in other words, with an idle cord circuit, inasmuch as there is one line connector for each cord circuit. The movement of this cord selector is brought-about upon the demagnetization of the rotary magnet 119. This magnet is adapted to attract the armature 120, which in turn moves the ratchet-pawl121 one tooth forward upon the ratchet wheel 122. At the same time the projection the series contacts 124 in the circuit of the rotating ma net 119 and permits the armature 120 to lae drawn back'by the tension spring 125, thus moving the brushes 115 and 116 from the contacts 113 and 117 to the next following set-of contacts, and if this next followin' set of contacts connects with a cord circuit which is already busy the cord selector will continue to actuate until the brushes 11.5 and 116 connect with an idle cord circuit.

The contacts 124 of this device as Well as the contacts 700i the line connector are mechanicallylnarranged so as to remain brokenn'ntil the armatures of the magnets have returned to their normal positions, at which time the contacts Wlll be again closed.

In this manner the armatures are caused to make their full stroke every time the circuit through the contacts is closed.

123 separates and 85 of relay connected with the top cord circuit and that, the next two cord circuits will be connected by the brushes 115 and 116 as the cord selector rotates. It will be understood further that the cord selector 114 has contacts through its entire circumference, and that it is adapted to rotate continuously in one direction. The line connectors 36, however, are adapted to rotate in both directions, being rotated clockwise by the step by-step mechanism and being returned to the starting point by a coil springflnot shown in. the drawing) when the release magnet is energized and again deenergized. In the operation of thissystem, referring particularly to Fig. 1, the call will be considered as originating at subscribers station No. 1. When this subscriber removes his receiver 7 from the switch-hook 8 he coinpletes a path for current from the live pole of battery A, through contacts 16 and 26 of master relay 17, conductor 25, contacts 15 and 14 of line relay 13, conductor 12-, con tacts 10 and 9 of cut-ofi" relay 11, line conductor a, transmitter 6, receiver 7, the contacts of switch-hook 8, line conductor 5 and the contacts 18 and 19 of cut-oil relay 11 to round. Current in this path'actuates the ine relay 13 changing all of its contacts to their abnormal condition. The actuation of contact 28 closes the circuit of contact 14 with the live pole of battery B and thereb interrupts the circuit of the battery through contact 15 of relay 13. The completion of the connection between contacts 29 and 30 closes the-circuit from the live pole or battery A through the coil of master relay 17, conductor 31 and contacts 30 and 29 of relay 13 to ground. Current in this path actuates the master relay 17 holding its contacts 16 and 26 open and removing attery from the Wire 25. Theclosing of contacts 33 and 34 of relay 13 connects the contacts 35 and 37 of the line connector 36. The connection of. contacts 29 and; 30 of relay .13 also completes the circuit from the live pole of battery C 66, conductor 86, the coil of the rotary magnet (59, the normally closed contacts 71, the now closed contacts 117 and 116 of the idle-cord selector 114i, conductor through contacts 84 31 and the contacts 30 and 29 of relay 13 l to ground. Current in this path actuates the rotary magnet 69 of the line connector 30. lhc actuation of the rotary magnet 69 attracts its armature 70 causing the pawl 68 l to cngagjc the tooth upon the ratchet 'Wl'lfifil 6? and also causing; the contactsll to he I criorlically intcrru 'itwl whereby the circuit through the coil of the rotary magnet 09 will la; periodically completed and the line connectcr will lit, sleppcil around one step at a tfnic until tho wiper 2 arrivcs at and makes connection with tho contact "l /hon this wiper cluinccts with the contact 3-3 a. path for currcut is coni ilctcil from the ll\'U polo ol llattcry C through lhc coil of rclay on, contacts (15 and (i-lof rclay (3(3 0011' rluctor (3 contacts and 3.3 oi the line conuectcr 30. ihc now closed contacts 3?; and il-l rclay lll conductor and the coil of the cut-oll' relay ll to ground. Currentin this path will actuate the cut-oil relay ll and the cord rclay (50. 'lho actuation of the cuboll' relay pcrforms the usual function of interrupting the circuit of the line relay and. connecting the liinhs of the line with the contacts of the multiple jacks and with the contacts of the line connector. 'lhc actuation of COl'll relay 0b interrupts the a current through its contacts 85 and 84: which are in series with the rotar magnet 09 oi the line connector and thcrcay stops thorotation of the line connector leaving it slanc'c ing with its thri-e wipers 52 and 02 in connection with the contacts 38, 37 and 35. The connc lion of contact 8i with the contact 101 of relay 60 completes a path for current from the live pole of battery C through contacts 84; and 101 of relay 0t; througl'i conductor 11.2, contacts 113 and ll?) of the iulccord selector 1H, through the contacts 12-5: of that selector and the coil of the rotary niag'nct lli-l to ground. Current in this path aclual'cs the rotary inan'nct and steps the idle cord selector one step forward such that it is in connection with the ncxt iillc C I'll circuit and lhc ncxc ltlli) lino conncctcr. The actuation of relay 00 also completes a circuit from the live pole of bah tery C through contacts S-l and. 101, thence through contacts 99 and 98 of relay Ell. and through the call lamp 100 to ground.

The operator, when she sees the call lamp 100 rlisplafvctl, throws hcr listening key and inquires the desired number. When the listening hey 9-1- is thrown the circuit of the coil of relay 8]. is completed through the auxiliary contacts 03 and 95 of the listening" lacy 94. Therefore, current flows from the live pole of battery C through the coil cl rcla 06, the now closed contacts ancl 83 of that relay, conductor 53, contacts 52 37 of tho lino connector, conductor the now closccl contacts and ll of cut-oil rell, lino t'ansniittcr 0., receiver '7.

rcnt in this path maintains thenctuation of relay 66 and actnatcs relay ill. The actn ation of relay 81 closes a locking circuit for itself including its contacts 96 and 0? which are in parallel with the contacts 93 and 95 of the li -zleuing hey 941 and also scvcrs circuit of the calllamn 100.

The completion of the circuit hotwccn contacts 99 and 102 f relay 8i completes a. circuit from the live pole of hatteryfl through contacts 8% and 101 of relay 66, contactc 09 and 102 of relay 8i, conductor 103 ancl coil of the release magnet 76 to ground. actuatcs thereleasc magnet which is to release the line connector only after it has been energized. anal again lencrgizccl. Efhc cncrgization of the release inagnct l0 attracts the armature 77 and causes the projection 73 n on the arm 72 to catch. back of the pro ection 74; upon the retain ing pawl 75. When the circuit is again broken through the release magnet, which does not occur untilthe conversation is ter niinateri, the spring connected with armature draws the armature hack to nor:- all positionand pulls the pawl out of engagement with the ratchet 67. The orator now tests the idle or busy condition. of the desired line, inserts her calling "plug and rings upon the line in the usual way. Upon the insertion of the. plug, cur rent flows from the live pole of battery C- tln'ougzlithe coil of relay 80, concln'ctor 50, contacts 57 and 58 of the ringing key, sleeve contacts 55) and '23 of the plug anti conductor 92 and the coil of cut-05:1 relay 11 to ground. The current in this path ac tuates the relays and ll. The actuation of relay 11 disconnects the line apparatus from the limbs of the telephone line and connects the telephone line directly with the contacts of the jack. The actnation of relay 80 closes its normally open contacts and. S9 and completes the circuit of the calh ing supervisory lamp 92, displaying this lamp. When the called subscrilocr answers his call the circuit is completed from the livcpole of battery C through tho conluctors formerly described to the 20 of the c11t-cll.relay ll, thenccthrouggh contact 9, line conductor l, transmitter 6'", receiver '7', switclihook 8", line conductor 5, contacts 18'- and- 21'. of cutoff relay 11', tip contacts 24' and 50 of the jack anal plug, contacts 4.7 aml 48 or the ringing key 49, conductor 46, the now closccl contacts 105 104 of relay 80 and the coil of re:- lay 82 to the ground pole of battery C The current in this path actuates relay 82 2 *l ell-aces the calling supervisory signal Dnring'conversation the battery current for wing the substation transmitters is Eur (l calling: line through the cc'ls fiti ancl 81 and to the through the fi lllllhl c2? 50 i ihen the called subscriber hangs up his receiver he interrupts the circuit of relay 82 causing that relay to fall back and. again complete the circuit of the calling supervisory signal 92. When the calling subscriber hangs up his receiver he interrupts the circuit of the relay 81. When this relay falls back it opens the contacts 99 and 102 and severs the circuit through the release magnet 76 of the line connector 36 allowing the armature of that magnet to return to its normal position, drawing the retaining awl 75 with it and releasingthe ratchet w eel 87 such that the wipers 4:2, 52 and 62 return to their normal positions. When this is done the circuit of relay 66 is interrupted at the contacts of the line connecting switch and contacts 84 and 85 oi? relay 66 are closed and complete the circult of the calling supervisory signal 87. W hen the operator observes the two supervisory si nals displayed she removes her calling plug from the jack and thereby severs the circuit through the relay 80 allowing that relay to fall back to its normal position and interrupt the circuit through both the calling and answering supervisory signals. The signals are now all out at the central oliice and the apparatus has again resumed its normal position with the exception that the cord selectbig switch 11-1 now stands in connection with the next cord circuit such that if the same subscriber, No. 1, should again call he would not be connected with the same cord cir uit but would be connected with the u xt following cord circuit.

The relation cl the cords, lines and connectors is shown in Fig. 2 and it is to be understood thad the multiple jacks on the right may or may not be connected with the contacts of the line connectors here shown.

T here may be one hundred lines for each switch-board section and ten connectors for one hundred lines which would be suliicient to permit one tenth of the subscribers to tall; at one time as calling subscribers or would permit one fifth of all of the subscribers to be in conversation. (if course, these numbers are immaterial and ma" "e varied r'clifferent conditions.

nle my systen hown in combination with many details 1/ s to be understood many or these are not essential and may be omitted or changed without in any :purting' from the spirit or scope of I vmention.

I claim:

1. in a telephone system, the combination with a plurality of telephone lines, of a cord circuit to connect therewith for conversation, a switch individual to the cord circuit, a plurality 9t contacts associated with said switch and arranged in groups, each group being associated with one of said telephone lines, one contact oi. each of said groups being normally disconnected and adapted to be connected to earth when its associated line is calling the central ofiice, a cut-ofi relay connected in circuit between said earth connection and said contact, means normally passive but effective upon initiation of a call to give said switch an independent movement until the movable contacts of said switch arrive upon the contacts of the line which is calling, a relay for the cord, and a series circuit closed upon such connection to energize said cut-oil relay and said cord relay to render said moving means inert, substantially as described.

2. In a telephone system, the combination with a plurality of telephone lines, a line and cut-0H relay for each of said lines, a source of current normally connected with all of said lines,'the actuation of any line relay being adapted to remove said source from its connection with all of the rest of the lines, substantially as described.

3. In a telephone system, the combination with a plurality of telephone lines, of a line and a cut-ofi relay for each of said lines, a cord circuit to connect ,with the lines for conversation, a supervisory relay and a connector switch for said cord circuit, the actuation of one of said line relays being adapted to set an idle connector switch into operation and to cause its contacts to move to the contacts associated with the calling line, a circuit including the cut-off relay of the line and a supervisory relay of the cord circuit completed through the contacts of the connector switch for interrupting the circuit of the line relay, and contacts on said supervisory relay interrupt-ed res onsive to its said energization to interrupt he movement of said switch, substantially as described.

4. In a telephone system, the combination with a plurality of telephone lines, of a line and a cut-oil relay for each of said lines, a cord circuitto connect with the lines for conversation, a supervisory relay and a connector switch for said cord circuit, the actuation of one of said line "clays being adapted to set an idle connecto' switch into operation and to causeits contacts to move to and stop upon the contacts associated with the calling line, and an energizing circuit, including the cut-off relay of the line and a supervisory relay of the cord circuit completed through the contacts of the connector witch. for interrupting the circuit of the line relay, the release of said line relay and energlzation of said supervisory relay being adapted to interrupt the circuit of the motor magnet of said connector switch at said line and supervisory relays, substantially as described.

5. In a telephone system, the combination with a plurality of telephone lines, of line and cutoff relays for each of said lines, a

- cord circuit, a

arran e v supervisory relay therefor, an automatic switch adapted to connect said cord with any line, an operating magnet therefor, an energizing circuit for said magnet adapted to be completed through con tacts of any line relay upon initiation of a call from its line, and a supervisory relay for the cord for opening said circuit.

15. In a telephone,system, the combination with telephone lines, of an operators cord circuit, an automatic connector switch,

means actuated upon initiation of a call to cause said switch to connect the cord with a calling line, a release magnet for said switch energized upon the response of the operator, and means under the control of the calling subscriber to deenergize said magnet.

16. In a telephone system, the combination with a calling telephone line, of a line relay for said line energized upon the initiation of the call, a cord circuit, an automatic switch individual to the cord for connecting said cord and said line, a motor magnet for said switch, and an energizing circuit for said magnet closed through contacts of said line relay upon energization thereof.

17. A telephone system comprising telephone lines, a line relay for each of said lines, a common relay for said line relays, a source of current connected through contacts of said common relay to each of said line relays, and circuit connections whereby whena line relay is energized the common relay is energized to disconnect said source from the other of said line relays and maintain the last said line relay energized, link circuits common to said lines, and means responsive to energization of the line relay for connecting the calling line with an idle one of said link circuits whereby said line and common relays are 'againdenergized.

18. A telephone system comprising tele phone lines, a line relay for each of said lines, a. common relay for said line relays, a source of current connected through contacts of said common relay to each of said line relays, automatic switches responsive to said line relays for extending the circuit of said telephone lines when calling, said common relay also being responsive to the actuation of any one of said line relays to disconnect said source of current from the other line relays to prevent their operation.

19. A telephone system comprising telephone lines, a line relay and source of'encrgizing current connected with each of said lines, operators cord circuits, automatic switches for extending the talking circuit of .said telephone lines to idle ones of said operators circuits responsive to said line relays, and: means also responsive to the actuation of one of the line relays to interrupt the energizing circuit of the other of said line relays to prevent their operation.

20. A telephone system comprising telephone lines, a line relay and source of current connected with each of said lines, line selectors responsive to said line relays for selecting said lines when calling, and means also responsive to the actuation of one ofthe line relays to prevent a simultaneous operation of any of the other line relays.

21. A telephone system comprising, tele-' phone lines, a' line relay and source of cur-"- rent connected with each of saidflines line selectors responsive to said line relays for selecting said lines when calling, andmeans effective upon actuation of one 'ofthe" line relays to start a line selector and to prevent a simultaneous operation of any of the other line relays until the first calling line is Se lected. V

A telephone system comprising telephone lines, a line relay and source of current connected with each of said lines, line selectors responsive to said line relays for selecting said lines when calling, a relay common to said line relays, means etl'ective upon actuation of one of said line relays to start a line selector in searchof'the calling line, said common relay also being responsive to actuation of a line relay to prevent a simultaneous operatipn of any-of the other line relays until. the first calling line isv selected 1 as 23. A telephone system comprising te1e phone lines, a line relay and source of cur rent connected with-each of said lines, line selectors responsive;to said line relays for selecting said lines When calling, means also responsive to the actilation' of one of the line relays to preventwa,simultaneous operation of any of the otherfline relays until the. calling line is selected, and a cut-off relay for each of said lines efiective upon connection made with the line by a line selector to restore the actuated line relay.

24. A telephone system comprising a telephone line, a line selector, a cord circuit for said'line selector, a supervisory relay for the cord circuit adapted to be energized upon connection made With said line by the line selector, a motor magnetfor the line selector, a line relay, and an energizing circuit for the motor magnet including normally open contacts of the line relay and normally closed contacts of the supervisory? relay.

' 25. A telephone system comprising a telephone line, line and cut-oft relavs for said line, a line selector having a cord circuit in- 129 dividual thereto, a supervisory relay for the cord circfiit, a motor magnet for the line selector, an energizing circuit for the motor magnet including normally open contacts of the line relay and normally closed contacts of the supervisory relay whereby when said line relay is operated said motor magnet operates said selector to connect with the line when calling, and a circuit including said cut-oil and supervisory relays adapted .9

to upon such conneccion Wherelo :7 supervisory relay is energized to interropt "circuit of the motor magnen.

52G. J-l telephone system comprising telehone lines, a line relay for each of said lines,

. ieccors, a master SWiLCu caving contacts cooperating Wiper, a; motor magnet ouch oil ssinl line selectors connected with on. individual contact of the master switch, con cctions extending from the Wiper of soiil f'er switch to normally open contacts ill off each of line relays, a source of current having one pole connected to said motor mogu s-ls and the other pole to contacts on l ;he line relays whereby when a line relay is energized an operating circuit is established through the Wiper of the master switch and on associated contact to the connected motor magnet 27. A telephone system comprising telephone lines, operators link circuits for eX- tenclin hc circuits of said lines, a signal for each of ssicl linlc circuits, automatic switches for interchangeably connecting igliree'o and means con-trolled over the connected csllin line for {Winn oocratin soul .e'nal t 1:: A h -0 for disconnection.

A telephone SYSc-Blll comprising celephone lines, operators link circuits ior ere tending the circuits of soul lines, lip and.

sleeve supervisory relays for said linlc. circuits, means nornmlly rendering the tip relay inoperative, a supervisory signal and opcrutng circuit therefor inclruiling' contacts of said relays, automatic switches for interchangeably connecting said lines when calling and said linlr circuits. means responsive to such a connection. to energize the sleeve supervisory relay and close the energizing circuit to operate said signal to indicate the call, means controlled by the operator for rendering said tip supervisory relay ellective to eflace said signal, said tip supervisory relay being thereby controllable over the connected line for again operating said signal for disconnection.

Signed by me at Chicago, county of Cook, and State of Illinois, in presence oi two Witnesses.

ALFRED l-ll ll ElSS.

Wl tnesses (Inn-roan C. BnAnnnnY, lrlAnJonIn l5. Gross. 

